基于盆栽试验的地膜残留对土壤微生物的影响

Effect of Plastic Film Residue on Soil Microorganism Based on Pot Experiment

地膜残留已经成为中国近年来农田生态环境的关注焦点。以西安市南郊东姜村蔬菜基地为土壤取样地,基于盆栽试验,研究不同地膜残留累积水平下,紫花苜蓿出苗期、初花期和采收期土壤中细菌、真菌、放线菌和微生物总量在数量上的变化规律。结果表明:随着地膜残留累积水平的增加,土壤中细菌数量虽呈下降趋势但不明显,最大下降幅度为14.38%(相对于CK),各生长期影响程度排序为出苗期>初花期>采收期。土壤中真菌数量均呈现明显下降趋势,但变化过程不同。出苗期,土壤中真菌数量的下降速率呈现"慢-快-慢"的变化过程;初花期和采收期,土壤中真菌数量的下降速率呈现"慢-快"的变化过程,最大下降幅度为87.93%(相对于CK)。说明地膜残留累积量的变化对土壤中真菌影响非常明显,各生长期影响程度排序为初花期>出苗期>采收期。土壤中的放线菌数量均呈现明显下降趋势,但变化过程不同。出苗期,土壤中放线菌数量的下降速率呈现"慢-快"的变化过程;初花期和采收期,土壤中放线菌数量的下降速率呈现"慢-快-慢"的变化过程,最大下降幅度为62.78%(相对于CK)。说明地膜残留累积量的变化对土壤中放线菌影响明显,各生长期影响程度排序为初花期>采收期>出苗期。土壤中微生物总量均呈现明显下降趋势且变化过程基本一致,最大下降幅度为38.16%(相对于CK)。说明地膜残留累积量的变化对土壤微生物总量影响显著,各生长期影响程度排序为:初花期>采收期>出苗期。结合累积年限和单位农田面积地膜残留累积当量,给出了不同地膜残留累积量下造成土壤中微生物总量下降的主要菌落。希望研究结果能为农田地膜残留治理和生态环境恢复提供理论基础。

Plastic film residue has become a focus of ecological-environment in Chinese farmland recently. Dongjiang vegetable base located in the south suburb of Xi ＇ an was taken as soil sampling area, based on pot experiment, the regularity for quantity change of bacteria, fungi, actinomycetes and microbial biomass in the soil in alfalfa＇s different growth period such as seedling stage,early florescence stage and harvesting stage at different plastic film residue levels. The results showed that with the increase of plastic film residue level,the quantity of the bacteria in soil decreased,but not obvious. The max decrease of the bacteria was 14. 38% compared with CK. The effect of plastic film residue levels on bacteria quantities with growth period were in orders： seedling stage〉early florescence stage〉 harvesting stage. The quantity of the fungi in soil presents an obvious decreasing trend, and with growth periods. At seedling stage ,the decrease rate of the fungi quantities presented trend of ＇ slow-fast-slow＇tat early florescence stage and harvesting stage, the decrease rate of the fungi quantities presented trend of ＇slow-fast＇. The max decrease of the fungi quantities was 87. 93% compared with CK. Therefore, the variation of plastic film residue level impacted the quantity of fungi very obviously. Changes of fungi quantities impacted by growth period order of the plastic film residue levels was early florescence stage 〉seedling stage〉harvesting stage. The quantity of the actinomycetes in soil presents a decrease,and it was different different growth periods. At seedling stage,the decrease rate of the actinomycetes presented a ＇slow-fast ＇ trend;at early florescence stage and harvesting stage,the decrease rate of the actinomycetes quantities presented a trend of ＇slow-fast-slow＇ trend. The max decrease of the actinomycetes was 62. 78% compared with CK. Therefore, the variation of plastic film residue level impacted the quantity of actinomycetes obviously. Changes of actinomycetes quantities impacted by growth period order of the plastic film residue levels was early florescence stage〉harvesting stage〉seedling stage. The microbial biomass in the soil presented an obvious variation trend of decrease at different growth periods. The max decrease of the microbial quantities was 38. 16% compared with CK. Therefore,the variation of plastic film residue level impacted the microbial quantities obviously. Changes of microbial biomass impacted by growth period order of the plastic film residue levels was early florescence stage, harvesting stage,seedling stage. The main microbiology colony caused the quantities decrease of microbial biomass at different plastic film residue levels was given according to cumulative years and cumulative quantity of the plastic film residue in a unit farmland area. It was hoped that the research results could provide theoretical basis for the treatment of plastic film mulching and ecological environment restoration.